Miter saw with wear plates and orientation system therefor

ABSTRACT

A device has a base which supports a rotatable table. The device includes a three position locking system. The first position locks the table to the base, the second position releasably locks the table to the base and the third position permits free rotation of the table on the base. A lever assembly and locking rod move a locking spring into the three positions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/273,724 filed on Oct. 18, 2002 which is a divisional of U.S. patentapplication Ser. No. 08/761,035 filed on Dec. 5, 1996, now U.S. Pat. No.6,474,206 issued on Nov. 5, 2002, which is a non-provisional applicationof 60/008,516 filed on Dec. 12, 1995. The disclosure of the aboveapplications are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to compound miter saws or other poweroperated equipment or machinery utilizing a cutter for performingworking operations on a workpiece. More particularly, the presentinvention relates to improvements in the table assembly for the miteradjustment for such power operated equipment. The table assemblyincludes a three position locking mechanism and a set of orientated wearplates.

BACKGROUND OF THE INVENTION

Saws and other apparatuses designed for cutting or performing otherworking operations on a workpiece typically require adjustmentmechanisms for moving the saw blade or cutting tool into an angularrelationship to the workpiece. Examples of such equipment includecross-cut compound miter saws which are adapted for allowing the user toselectively move the saw blade into any of a number of positions ormodes for square cutting, miter cutting, bevel cutting, or compoundmiter cutting where a combination miter and bevel are cut. In addition,some operations, such as dado cutting or shaping operations, forexample, require the use of saw blades or other cutting or workingdevices of different shapes or sizes to be substituted for one anotherin order to perform the desired operation on the workpiece, whether theworkpiece is composed of wood, plastic, metal or other materials.

In order to allow for the adjustment in miter and bevel angles, the sawblade, cutter or other working device is angularly adjustable withrespect to a horizontal base and a vertical fence against which theworkpiece is positioned. The miter adjustment allows the saw blade,cutter or other working device to move angularly with respect to thevertical fence while maintaining perpendicularity with the horizontalbase. The bevel adjustment allows the saw blade, cutter or other workingdevice to move angularly with respect to the horizontal base whilemaintaining perpendicularity with the vertical fence. At times it may bedesirable to cut a combination miter and bevel by simultaneouslyadjusting the angularity of the blade with respect to both thehorizontal base and the vertical fence.

Once the saw blade, cutter or other working device has been adjusted tothe desired position with respect to the horizontal base and thevertical fence, locking mechanisms for the miter and bevel adjustmentmust be activated in order to prohibit movement of the saw blade, cutteror other working device with respect to the base and fence while thecutting operation is performed. These locking mechanisms need to beeasily activated, adjustable and quick acting in order to optimize theefficiency of the cutting apparatus and provide convenience to theoperator of the apparatus.

SUMMARY OF THE INVENTION

In accordance with the present invention, an improved table assemblyincorporating a miter locking mechanism is employed. The lockingmechanism includes an axially extending rod which has a three positionallever assembly at one end and a rod spring at the opposite end. The rodspring is utilized to engage a series of detents arranged at the variouspopular miter angles as well as locking the table at the desired miterangle. The lever assembly is movable between a first position where themiter table is locked at a specified position, a second position wherethe miter table is releasably held by the detents at one of the variouspopular miter angles and a third position where the detents areby-passed, thus allowing for adjustment of the table to a position inbetween miter detents. In addition to the improved miter lockingmechanism, the present invention includes a unique set of wear platesdisposed between the table assembly and its supporting base. The wearplates incorporate features which ensure their correct orientationduring assembly of the miter saw.

Other advantages and objects of the present invention will becomeapparent to those skilled in the art from the subsequent detaileddescription, appended claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings which illustrate the best mode presently contemplatedfor carrying out the present invention:

FIG. 1 is a front perspective view of a sliding compound miter saw inaccordance with the present invention;

FIG. 2 is a front elevational view of the sliding compound miter sawshown in FIG. 1;

FIG. 3 is a rear elevational view of the sliding compound miter sawshown in FIGS. 1 and 2;

FIG. 4 is a side elevational view of the sliding compound miter sawshown in FIGS. 1 through 3;

FIG. 5 is an assembled perspective view, partially in cross-section ofthe table assembly shown in FIGS. 1 through 4;

FIG. 6 is an exploded perspective view of the miter locking mechanism inaccordance with the present invention;

FIG. 7 is a plan view of the miter saw base illustrating the fool-proofassembly of the wear plates in accordance with the present invention;and

FIGS. 8A-8C are cross-sectional side views of the miter lockingmechanism in accordance with the present invention showing the mechanismin its various positions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in which like reference numerals designatelike or corresponding parts throughout the several views, there is shownin FIGS. 1 through 4 an exemplary sliding compound miter sawincorporating a table assembly in accordance with the present invention,shown merely for the purposes of illustration, and designated generallyby the reference numeral 10. One skilled in the art will readilyrecognize from the following description, taken in conjunction with theaccompanying drawings and claims, that the principles of the presentinvention are equally applicable to sliding compound miter saws,compound miter saws, chop saws, radial arm saws, table saws or othersaws of types other than that shown for purposes of illustration in thedrawings. Similarly, one skilled in the art will readily recognize thatthe principles of the table assembly according to the present inventionare also applicable to other types of powered or unpowered equipment forperforming an operation on a workpiece. Such equipment includes, but isnot limited to, dado saws, spindle shapers or sanders, or other types ofpowered or unpowered devices that would benefit from the table assemblyof the present invention.

Referring primarily to FIGS. 1 through 4, sliding compound miter saw 10comprises a base assembly 12, a table assembly 14, a housing assembly16, a saw blade 18, a blade guard 20, a motor 22 drivingly connected tosaw blade 18, a handle 24 and a fence assembly 26. Table assembly 14 issecured to base assembly 12 such that it can be rotated in order toprovide adjustment for miter cutting. The rotation of table assembly 14changes the angle of saw blade 18 relative to fence assembly 26 butmaintains the perpendicularity of saw blade 18 with table assembly 14. Alocking mechanism 28 can be activated in order to lock table assembly 14to base assembly 12.

Housing assembly 16 is secured to table assembly 14 such that it can bepivoted with respect to table assembly 14 in order to provide adjustmentfor bevel cutting. As can be appreciated by one skilled in the art, theadjustments for mitering and beveling can be separate or they can beadjusted simultaneously in order to provide a compound miter and bevelcut. The pivoting of housing assembly 16 changes the angle of saw blade18 relative to table assembly 14 but maintains the perpendicularity ofsaw blade 18 with fence assembly 26. A locking mechanism 30 can beactivated in order to lock housing assembly 16 to table assembly 14.

Referring to FIG. 5, the present invention is directed towards tableassembly 14 and locking mechanism 28 which locks table assembly 14 tobase assembly 12 at any specified miter angle. Base assembly 12 definesa circular mounting structure 40 which includes a cylindrical cup shapedmounting boss 42 for mounting a table 44 as will be described laterherein. Base assembly 12 also defines a plurality of threaded apertures46 which are used to mount a detent plate 48 using a plurality of bolts50, only one being shown in FIG. 5. Detent plate 48 defines a pluralityof slots 52 which correspond to the plurality of threaded apertures 46in order to allow for the securing of detent plate 48 to base assembly12 by bolts 50. The plurality of slots 52 permit adjustment of detentplate 48 to ensure the proper relationship of the pre-specified miterangles. Detent plate 48 further defines a plurality of detents 54 whichare located at various popular miter angles for saw 10. Detents 54 workin conjunction with locking mechanism 28 to locate table 44 at one ofthe various popular miter angles as will be described later herein.

Table assembly 14 includes table 44 and locking mechanism 28. Table 44is a circular plate-like member defining a work supporting surface 56and a mounting boss 58. Table 44 is rotatably mounted to base assembly12 by inserting boss 58 of table 44 into boss 42 of base assembly 12. Abolt 60 is inserted through table 44 and threadably received within athreaded bore 62 (FIG. 7) in base assembly 12 to complete the assembly.Bolt 60 is tightened enough to secure table 44 to base assembly 12 butit is not tightened to the point of restricting rotation of table 44with respect to base assembly 12. The threads on bolt 60 incorporate apatch lock to lock bolt 60 in position once it has been tightened.

Table 44 rotates with respect to base assembly 12 in order to change themiter angle of saw 10. This rotation of table 44 changes the angularrelationship of saw blade 18 with respect to fence assembly 26 but doesnot change the angular relationship of saw blade 18 with respect totable 44. Disposed between table 44 and base assembly 12 are a pluralityof wear plates 64. Wear plates 64 provide a surface to support table 44as well as reducing the friction and wear between table 44 and baseassembly 12. Wear plates 64 are preferably manufactured from springsteel and protect base assembly 12 which is preferably manufactured fromaluminum from excessive wear that would cause excessive play betweenbase assembly 12 and table 44 leading to cutting inaccuracy.

Referring now to FIG. 7, wear plates 64 are preferably manufactured frompre-hardened steel using a stamping operation. This stamping of wearplates 64 forms a burred edge on one side of wear plates 64 which needsto be positioned against the stationary base 12 such that these burrededges do not interfere with the fit or rotation of table 44. In order toensure proper orientation of wear plates 64, they are each provided witha first end 66 being cut along a radial line or perpendicular to atangent line at that point and a second end 68 being cut at an acuteangle to a radial line or an acute angle to a tangent line at thatpoint. Base assembly 12 is provided with a plurality of formed shoulders70 each of which defines a first surface 72 corresponding with first end66 on plates 64 and a second surface 74 corresponding with second end 68on plates 64. Surfaces 66, 68, 72 and 74 fool-proof the assembly ofplates 64 to base assembly 12 by allowing only one orientation of eachwear plate 64 with respect to base assembly 12 thus ensuring that anyforming burr on wear plates 64 is positioned towards base assembly 12and not towards table 44. Base assembly 12 includes a circumferentiallyextending ring 76 which is disposed between adjacent shoulders 70 tosupport and position wear plates 64.

Referring now to FIG. 6, locking mechanism 28 comprises a housing 80, alocking lever assembly 82, a threaded locking rod 84 and a lockingspring 86. Housing 80 is a generally hollow rectangular member which isfixedly secured to table 44 such that it extends radially outward fromtable 44. Housing 80 is positioned on table 44 such that when saw blade18 is positioned perpendicular to fence assembly 26, or a 0° miterangle, housing 80 is also generally perpendicular to fence assembly 26.Thus housing 80 is generally parallel to saw blade 18. Lever assembly 82comprises locking lever 87 and detent trigger 89. Locking lever 87 anddetent trigger 89 are pivotably secured to the outside end of housing 80by a pin 81 and the threaded end of rod 84 is threadingly received in apin 83 which is rotatably secured to detent trigger 89 with rod 84extending from detent trigger 89 towards table 44. A coil spring 97biases detent trigger 89 away from locking lever 87. Spring 86 isfixedly secured to table 44 by a pair of bolts 88 and defines anaperture 90 which slidingly accepts the opposite end of rod 84. Spring86 is a generally U-shaped component with one leg of the U defining aspring detent 92 and the opposite leg of the U defining a locking tab94. When spring 86 is assembled to table 44 and table 44 is assembled tobase assembly 12, spring detent 92 is in biased engagement with detentplate 48 to define a detent system between table 44 and base assembly 12and locking tab 94 is positioned adjacent to a cylindrical surface 96located on base assembly 12. In order to increase the load with whichspring detent 92 is in biased engagement with detent plate 48, a washer91, a coil spring 93 and a retainer 95 are assembled to rod 84. Retainer95 is fixedly secured to rod 84 and spring 93 reacts against washer 91and thus spring detent 92 to increase the load with which spring detent92 is biased into engagement with detent plate 48.

Locking mechanism 28 can be located in any one of three positions by themovement of lever 82 as illustrated in FIGS. 8A-8C. Referring now toFIG. 8A, locking mechanism 28 is shown in its locked position withlocking lever 87 of lever assembly 82 being located at a positionapproximately 30° down from a horizontal position. In this position,locking lever 87 urges detent trigger 89 downward which urges lockingrod 84 towards table 44 which in turn engages locking tab 94 againstsurface 96 of base assembly 12 locking table 44 in position relative tobase assembly 12 at the specific miter angle. The load with whichlocking rod 84 engages locking tab 94 and surface 96 can be adjusted byrotating locking rod 84 within pin 83 to adjust the working length ofrod 84. A screw driver slot 85 is provided to facilitate this adjustmentand a patch lock is incorporated onto the threads of locking rod 84 toretain locking rod 84 in its desired location with respect to pin 83.

Referring now to FIG. 8B, locking mechanism 28 is shown in its engagedposition with locking lever 87 of lever assembly 82 being located at agenerally horizontal position. In this position, detent trigger 89 isspaced from locking lever 87 and locking rod 84 is disengaged fromlocking tab 94. Table 44 can now be rotated with respect to baseassembly 12. Spring detent 92 is in biased engagement with detent plate48, thus rotation of table 44 with respect to base assembly 12 willcause spring detent 92 to ratchet between the plurality of detents 54 toreleasably stop at the various popular miter angles for saw 10. Asdescribed above, in order to provide adjustability to saw 10, detentplate 48 is provided with slots 52 for securing plate 48 to baseassembly 12 using bolts 50. With spring detent 92 being positioned inthe “0°” detent, bolts 50 are loosened to allow table 44 to bepositioned with respect to base assembly 12 such that saw blade 18 isperpendicular to fence assembly 26. When the relationship between sawblade 18 and fence assembly 26 has been set, bolts 50 are tightened,securing detent plate 48 and thus table 44 to base assembly 12 in theproper orientation. Movement of table 44 between detents 54 will thencause the accuracy of saw blade 18 in relation to fence assembly 26 tobe dictated by the accuracy of the positioning of detents 54 in plate48. Because the accuracy of detents 54 and plate 48 are controlled by astamping operation, the positional relationship of detents 54 on plate48 can be controlled to tight tolerances thus ensuring the accuracy ofsaw 10. While the above adjusting process has been described using the“0°” detent in plate 48, it is within the scope of the present inventionto utilize any of the various detents 54 in plate 48 by checking theappropriate relationship between saw blade 18 and fence assembly 26 ifdesired.

Referring now to FIG. 8C, locking mechanism 28 is shown in its releasedposition with locking lever 87 of lever assembly 82 being located at thegenerally horizontal position and detent trigger 89 also being moved toa generally horizontal position. In this position, an annular collar 98,fixedly secured to rod 84 contacts spring detent 92 and moves itradially outward or away from detents 54. With spring detent 92 beingmoved out of engagement with detents 54, the movement of table 44 withrespect to base assembly 12 will occur without spring detent 92ratcheting between detents 54. This position of locking mechanism 28 isespecially useful when locating table 44 at a miter angle which is notpre-defined by one of detents 54 or when locating table 44 at a miterangle which is close to one of the pre-defined miter angles. Whenlocating table 44 close to one of the pre-defined miter angles, therelease of spring detent 92 eliminates the tendency of the system tojump into the adjacent detent thereby making it difficult to set a miterangle close to but not exactly equal to one of the pre-defined miterangles.

While the above detailed description describes the preferred embodimentof the present invention, it should be understood that the presentinvention is susceptible to modification, variation and alterationwithout deviating from the scope and fair meaning of the subjoinedclaims.

1. A device for performing operations on a workpiece, the devicecomprising: a base; a table rotatably secured to the base; a leverassembly pivotably secured to the table; a locking spring secured to thetable; a locking rod extending between the lever assembly and thelocking spring, the lever assembly moving the locking rod which movesthe locking spring between a first position where the locking springengages the table to lock the table to the base, a second position wherethe locking spring releasably holds the table to the base and a thirdposition where the locking spring disengages the table to allow rotationof the table with respect to the base.
 2. The device according to claim1, wherein the lever assembly comprises a first lever pivotably securedto the table and a second lever pivotably secured to the table.
 3. Thedevice according to claim 2, wherein the first lever and the secondlever are pivotably secured to the table along a common pivot axis. 4.The device according to claim 1, further comprising a detent platesecured to the base, the detent plate defining at least one detent, thelocking spring engaging the detent when the locking spring is in thesecond position.
 5. The device according to claim 1, wherein the lockingspring comprises a generally U-shaped body having first and second legs.6. The device according to claim 5, wherein the first leg of the lockingspring engages the table in the first position.
 7. The device accordingto claim 6, wherein the second leg of the locking spring engages thetable in the second position.
 8. The device according to claim 5,wherein the second leg of the locking spring engages the table in thesecond position.
 9. The device according to claim 5, wherein the lockingrod extends through the second leg of the locking spring.
 10. The deviceaccording to claim 9, wherein the locking rod urges the first leg of thelocking spring into engagement with the table in the first position. 11.The device according to claim 10, wherein the locking rod moves thesecond leg of the locking spring out of engagement with the table in thethird position.
 12. The device according to claim 9, wherein the lockingrod moves the second leg of the locking spring out of engagement withthe table in the third position.
 13. The device according to claim 1,wherein the lever assembly comprises a first lever pivotably secured tothe table and a second lever pivotably secured to the table, the secondlever being disposed within a slot defined by the first lever.
 14. Thedevice according to claim 13, wherein the first lever and the secondlever are pivotably secured to the table along a common pivot axis. 15.The device according to claim 1, further comprising: a wear platedisposed between the base and the table; means for orientating the wearplate with respect to the base.
 16. The device according to claim 1,wherein the wear plate has a first face and an oppositely disposedsecond face, the orientating means locating the first face towards thetable.